Rheum plant named ‘Scarlet King’

ABSTRACT

A new and distinct  Rheum  plant named ‘Scarlet King’ characterized by early dormancy break, exceptional frost resistance, and deep pearlescent red coloration of early season growth.

Botanical denomination: Rheum spp.

Variety designation: ‘Scarlet King’.

BACKGROUND OF THE INVENTION

The present invention relates to a new and distinct cultivar of Rheum(rhubarb) given the cultivar name ‘Scarlet King’. Rheum is in the familyPolygonaceae. This new cultivar is a chance seedling of unknown originthat was discovered during an environmentally controlled indoor breedingprogram at Sconce Farms in Aurora, Oreg.

Compared to Rheum ‘Deacon’, unpatented, the new cultivar breaks dormancy2 or more weeks earlier in the Willamette Valley, Oreg. Compared toRheum ‘Crimson’, unpatented, the new cultivar breaks dormancy 3 or moreweeks earlier in the Willamette Valley, Oreg. The new cultivar is alsomuch more frost resistant than either ‘Deacon’ or ‘Crimson’ and has adeeper red color that extends throughout the stalk and into the veins ofthe leaves early in the growing season.

SUMMARY OF THE INVENTION

The following traits have been repeatedly observed and are determined tobe the unique characteristics of the new cultivar. These characteristicsin combination distinguish Rheum ‘Scarlet King’ as a new and distinctcultivar:

-   -   1. breaks dormancy in mid to late December in the Willamette        Valley, Oreg.;    -   2. exceptional frost resistance and able to withstand freezing        of the new growth without experiencing significant dieback or        induced dormancy; and    -   3. new early season growth shows deep pearlescent red coloration        on all sides of the stalk, with the deep pearlescent red        coloration extending from the base of the stalk into the veins        of the leaves.

This new cultivar has been reproduced only by asexual propagation(crown, or rhizome, division). Each of the progeny exhibits identicalcharacteristics to the original plant. Asexual propagation using crowndivision, as done in Aurora, Oreg., shows that the foregoingcharacteristics and distinctions come true to form and are establishedand transmitted through succeeding propagations. The present inventionhas not been evaluated under all possible environmental conditions. Thephenotype may vary with variations in environment without change in thegenotype of the plant.

BRIEF DESCRIPTION OF THE PHOTOGRAPHS

FIG. 1 shows a Rheum ‘Scarlet King’ growing in the ground approximately5 months after planting in a trial field in August in Aurora, Oreg.

FIG. 2 shows the stalks of Rheum ‘Scarlet King’ in August in Aurora,Oreg.

FIG. 3 shows stalk coloration of Rheum ‘Scarlet King’ harvested inAurora, Oreg., early in the growing season.

DETAILED PLANT DESCRIPTION

The following is a detailed description of the new Rheum cultivar basedon observations of five-month-old specimens growing in the ground infull sun under typical outdoor conditions in the trial fields in Aurora,Oreg. Observations were made in early August on plants that were plantedin April of the same year. Aurora is Zone 8 on the USDA Hardiness map.Temperatures range from an average high of 83 degrees F. in August to anaverage low of 35 degrees F. in December. Normal rainfall in Aurora is40.7 inches per year. The color descriptions are based upon The RoyalHorticultural Society Colour Chart, 3^(rd) edition.

-   Plant:    -   -   Type.—Herbaceous perennial.        -   Hardiness.—USDA Zones 3-8.        -   Size.—Approximately 100 to 140 cm wide and 50 to 70 cm tall.        -   Form .—Mound.        -   Vigor.—Excellent.-   Leaf petiole (stalk):    -   -   Type.—Long and ascending with an approximately D-shaped            cross-section, often flat to slightly convex on the upper            side, especially early in the growing season.        -   Size.—Approximately 3-4 cm wide, 2-3 cm deep, and 40-50 cm            long.        -   Surface texture.—Striate, often with a pronounced ridge on            each edge of the upper side.        -   Color.—Somewhat pearlescent, strong yellowish pink 37A with            brilliant yellowish green 149C striae (as observed in            August). Generally darker and pinker at the proximal end and            progressively becoming lighter and more green at the distal            end. Stalks are darker, more pearlescent, and more uniform            in color earlier in the growing season, exhibiting a strong            reddish orange 40C coloration that extends over nearly the            entire length.-   Leaf:    -   -   Type.—Simple.        -   Shape.—Cordate.        -   Size.—Approximately 35-40 centimeters in length and breadth.        -   Arrangement.—Basal.        -   Margins.—Entire and wavy.        -   Surface texture.—Chartaceous.        -   Venation.—Cross-venulate.        -   Color.—Deep yellowish green 141A.-   Cold resistance: Highly resistant to frost damage. Survives moderate    to heavy frost, starting in late December, without significant    dieback and/or induced dormancy.-   Timing: In Aurora, Oreg., the new cultivar breaks dormancy 2 or more    weeks earlier than the closest commonly grown cultivar, ‘Deacon’.    The new cultivar is generally 20-30 cm tall when ‘Deacon’ breaks    dormancy.

It is claimed:
 1. A new and distinct Rheum plant as herein illustratedand described.